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Spouse Irradiation: You can get a significant dose of radiation by sleeping with one (or two) women (Potassium 40 irradiation)

Lachlan Cranswick's homepage is at http://lachlan.bluehaze.com.au/

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Summary: Spouse Irradiation is total bollocks. Read on for details.

The Myth:

Spouse Irradiation: You can get a significant dose of radiation by sleeping with one (or two) women (Potassium 40 irradiation)


Background

It is a very common statement in the nuclear radiation industry that "You can get a significant dose of radiation by sleeping with one (or two) women (Potassium 40 irradiation)". The numbers used are compared to doses from the "lower" nuclear industry: thus putting the level of radiation dosage from nuclear reactors "in perspective".

(The humble scribe of this webpage had this (the two women argument) used against him around 10 years ago when complaining about getting zapped with a low/trivial dose of gamma rays due to poor equipment design and operation methods)

In theory, with some of the numbers quoted, it can be calculated that 15 cancer deaths a year in the US due "spouse" irradiation. (refer RADSAF archive extracts below)


Breaking the Myth

This is total bollocks. It is a myth propogated from mis-calculated numbers, but has proved hard to erradicate.

One laboratory is quoted as having tried this with radiation counters in place - and found no significant elevated radiation levels.

The humble scribe of this web page has been referred to Monte Carlo experiments (unpublished) which may even show the two women have a "shielding effect". These Monte Carlo calculations also included the possibility that the bed was a "water bed". (Radsafe quotes on this below).

For more detailed and conclusive information, check out the RADSAFE Mailing list archive at http://www.ehs.uiuc.edu/~rad/radsafe.html. This is a topic that has come up quite often and the relevant numbers are discussed there.

E.g.:

> ----------
> Date: 	Wednesday, December 08, 1999 9:37 AM
> Reply To: 	radsafe@romulus.ehs.uiuc.edu
> Subject: 	RE: estimates of human-human irradiations
> 
> Yes, most of the numbers you see for spousal irradiation are grossly in
> error, as can be shown by a back-of-the-envelope calculation.  Some time
> back I employed someone-else's idle student (he was between projects) to
> corroborate my calculations with some Monte Carlo runs using simple
> cylindrical phantoms on a water-bed.  As I recall, the agreement was good,
> so I gave a branch talk entitled, "Spousal Irradiation - Debunking the
> Folklore".
> 
> It's difficult to trace the origin of the incorrect data, but I think what
> may have happened (in at least one misinformation lineage) is that someone
> a few decades ago screwed up a calculation because they didn't bother to
> check the decay scheme of K-40, and the resulting number for spousal
> irradiation clearly exceeded the nuclear-power contribution to population
> dose (which may still be true for the correct number), and this comparison
> was too cute not to propagate (and further distort) geometrically. There
> are several other sources of significant error as well.  Assuming, for
> example, that Reference Man represents an average person, can introduce
> considerable error in the case of K-40.
> 
> ----------
> From: 	Lieskovsky, Miro[SMTP:MLieskovsky@nbpower.com]
> Reply To: 	radsafe@romulus.ehs.uiuc.edu
> Date: 	Wednesday, December 08, 1999 8:07 AM
> To: 	Multiple recipients of list
> Subject: 	RE: estimates of human-human irradiations
> 
> Kim,
> A quickie using MicroShield:
> 
> Source: 7kBq of K-40 in a sphere (water) with a 30cm DIA.
> 
> The exposure rate at 100cm from the sphere centre is ~1.2E-5mR/h, that's
> 0.012microR/h or ~1000times less than environmental exposure rates. At
> 30cm
> from the sphere centre it is ~1.4E-4mR/h. 
> 
>   :-)  However, I think, that a person standing in my
> 'too-close-for-comfort' zone shields off more radiation than s/he
> contributes.  Next time I hug my wife, I'll have a gamma meter on me....
> 
> 
> Regards,
> 
> Miro
> 
>  
> 
> -----Original Message-----
> From: Kimberlee Kearfott [mailto:kearfott@umich.edu]
> Date: December 8, 1999 12:40 AM
> To: Multiple recipients of list
> Subject: estimates of human-human irradiations
> 
> 
> Hi
> 
> I don't want to start an instoppable thread-- but has anybody 
> computed how much irradiation we get from standing by others, due to 
> our natural concentrations of radionuclides?  Any other similar 
> comparisons?
> 
> Kim Kearfott
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
> 


> ---------- > Date: Wednesday, December 08, 1999 9:51 AM > Reply To: radsafe@romulus.ehs.uiuc.edu > Subject: RE: estimates of human-human irradiations > > Case in point (with regard to my posting of three minutes ago)! > > > ---------- > From: M. Woo[SMTP:m-woo@uiuc.edu] > Reply To: radsafe@romulus.ehs.uiuc.edu > Sent: Wednesday, December 08, 1999 9:44 AM > To: Multiple recipients of list > Subject: Re: estimates of human-human irradiations > > Kimberlee Kearfott wrote: > > > I don't want to start an instoppable thread-- but has anybody > > computed how much irradiation we get from standing by others, due to > > our natural concentrations of radionuclides? Any other similar > > comparisons? > > Rick Strickert put together an amusing analysis of K-40 exposure that he > posted to the list back in 1995. Here is the excerpt from the archives: > > ====cut==== > Recent RADSAFE emails suggest a considerable concern about radiation > exposure from bananas. While I limit my banana intake to servings of > banana (brazil?) nut bread, there is a more serious source of K-40 > radiation poisoning. > > According to UNSCEAR (1988) the annual effective dose equivalent from > the body's K-40 is an estimated 180 uSv (18 mrem). Now, in the case > where two people share the same bed for 8 hrs/day, and assuming a > geometry factor of 0.16 (this is probably subject to considerable > variation; I don't want to discuss it), then each person would receive > an additional annual radiation dose of approximately 10 uSv (1 mrem) > from the other person's K-40. This does not take into account any > backscatter from a slab floor (a NORM problem itself!). > > There are at least 60 million married couples in the U.S. that I will > assume sleep together (you can supplement the number if you wish). > This results in a U.S population exposure of at least 1200 PYSv > (120,000 man-rem per year). (PC hawks - I'm using the dictionary's > first definition of 'man'.) > > Using 8,000 man-rems per lethal cancer (Wilson and Crouch, Science 236, > 1987, pp. 267-270), the sleeping together radiation dose equivalent > (STRDE) results in an estimated average of 15 deaths in the U.S per > year. ^^^^^^^^^ > > However, I don't think a lead-lined teddy will ever become popular. > ====cut==== > > -- > Melissa Woo, Health Physicist > Div. of Environmental Health & Safety > 101 S. Gregory St., MC-225, Urbana, IL 61801 > ph 217.244.7233 fax 217.244.6594 > ************************************************************************ > The RADSAFE Frequently Asked Questions list, archives and subscription > information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html


> ---------- > Date: Wednesday, December 08, 1999 3:33 PM > Reply To: radsafe@romulus.ehs.uiuc.edu > Subject: RE: human-human K-40 dose- Reduction due to shielding of > > The water was a Monte Carlo expediency, but the base case is sleeping > alone on the same bed, so it's not relevant to the problem modeled. > > Someone mentioned the second person acting as a shield from the natural > radiation background, which is a valid question. The code was run to > demonstrate an upper bound and tentative average annual dose from a > spouse's K-40 alone, so this was not considered. My feeling is that the > shielding effect is small for a typical source-target distance. > Terrestrial radiation and that from building materials would be the thing > to look at. I would think a crude first estimate of the dose spared could > be made from, say, taking the average annual terrestrial dose (and assume > house shielding is offset by activity in building materials, that is to > say I haven't the slightest idea), times 8/24, times an estimate of the > fraction of the relevant space eclipsed, divided by about 2 for > transmission, and ignore an add-back-in for the second person as a source > of scatter. Somebody want to run (or correct) those numbers? > > I believe shielding from cosmic rays can safely be ignored. The muon flux > goes roughly as the square of the cosine of the angle from vertical, but > let's not go there. Besides, most of the cosmic-ray dose is from muons > with prodigious energies, and they don't stop for anybody. > > > ---------- > From: Zack Clayton[SMTP:zack.clayton@epa.state.oh.us] > Reply To: radsafe@romulus.ehs.uiuc.edu > Date: Wednesday, December 08, 1999 1:33 PM > To: Multiple recipients of list > Subject: RE: human-human K-40 dose- Reduction due to shielding of > > I can't help myself. Has anyone floated an estimate of shielding by > sleeping on a water bed? > > I don't think this would be in the FAQ. > > Zack Clayton > Ohio EPA - DERR > email: zack.clayton@epa.state.oh.us > voice: 614-644-3066 > fax: 614-460-8249 > > ************************************************************************ > The RADSAFE Frequently Asked Questions list, archives and subscription > information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html >


> ---------- > Date: Monday, March 13, 1995 4:09 PM > Reply To: radsafe@romulus.ehs.uiuc.edu > Subject: RE: Worse than bananas > > This is an example of the type of sloppiness by legions of people claiming > doses of anywhere from 1 to 4 mrem per year from spousal K-40. This guy > doesn't want to discuss his geometry factor, but you don't have to to > demonstrate that he's an order of magnitude high in his dose estimate. > He's simply pro-rated the self-dose, neglecting to look at the decay > scheme and radiation energies. About 90% of the self-dose is from beta > particles, and about 10% from the 1461 keV gamma rays following electron > capture. It's only the gamma rays (notwithstanding a bit of > bremsstrahlung) and their Compton secondaries that are available to > irradiate your spouse, after some considerable self-attenuation (whence > the nominal 10%). I proposed a COG project a couple of years ago to > calculate and publish some sensible dose estimates for spousal > irradiation, but it got shot down. I did take advantage of an idle > student here a while back to have him do some Monte Carlo work that > verifies my back-of-the-envelope dose estimates using a conservative > (intimate (but abstract)) geometry. I'm keen to publish this, but it's > just never made the top of the list. > > > P.S. Oh yea, we modelled the mattress as a water-bed. > > ---------- > From: rick strickert > To: Multiple recipients of list > Subject: Worse than bananas > Date: Monday, March 13, 1995 1:32PM > > > -------------------------------------------------------------------------- > -- -- > Recent RADSAFE emails suggest a considerable concern about radiation > exposure from bananas. While I limit my banana intake to servings of > banana (brazil?) nut bread, there is a more serious source of K-40 > radiation poisoning. > > According to UNSCEAR (1988) the annual effective dose equivalent from > the body's K-40 is an estimated 180 uSv (18 mrem). Now, in the case > where two people share the same bed for 8 hrs/day, and assuming a > geometry factor of 0.16 (this is probably subject to considerable > variation; I don't want to discuss it), then each person would receive > an additional annual radiation dose of approximately 10 uSv (1 mrem) > from the other person's K-40. This does not take into account any > backscatter from a slab floor (a NORM problem itself!). > > There are at least 60 million married couples in the U.S. that I will > assume sleep together (you can supplement the number if you wish). > This results in a U.S population exposure of at least 1200 PYSv > (120,000 man-rem per year). (PC hawks - I'm using the dictionary's > first definition of 'man'.) > > Using 8,000 man-rems per lethal cancer (Wilson and Crouch, Science > 236, > 1987, pp. 267-270), the sleeping together radiation dose equivalent > (STRDE) results in an estimated average of 15 deaths in the U.S per > year. ^^^^^^^^^ > > However, I don't think a lead-lined teddy will ever become popular. > > > > Richard G. Strickert, Ph.D. | "Absolutum obsoletum - > Radian Corporation, Austin, TX | if it works, it's out of date." > Internet:rick_strickert@radian.com | - Stafford Beer > ---> "All written IMHO." <--- | >


> I had occasion recently to access (via the Canadian Nuclear Society page) > your page called Radiation and Life, and have the following comments for > your consideration. > > The activity of an adult human is given as 3 kBq. The actual activity is > closer to 7, and perhaps 8 kBq depending on some parameters involving age > and sex. The sex-averaged breakdown is nominally 3.5 kBq K-40, 3.3 kBq > C-14 (assuming the cosmogenic abundance, which has been somewhat > modulated), and 0.5 kBq Rb-87. Not included in this are other minor > contributors including H-3 and Cs-137, mostly man-made, and uranium- and > thorium-decay-series nuclides. > > The radon activity of a 100-square-metre home is given as 3 kBq. Given an > average room height of 3 metres, I note that this would represent a > concentration of only 10 Bq/m^3. This is very low, but may be applicable > to Australia. You may want to check your source. > > The specific activity of uranium is given as 10 MBq/kg. In fact, natural > uranium has a specific activity of nominally 25 MBq/kg, consisting of just > over 12 MBq of each of U-238 and U-234, and just under 1 MBq of U-235. At > the risk of sounding excessively critical, let me say that as the Uranium > Information Centre you've got to get that one right. > > The risk of getting cancer is given as 5% for an acute dose of 1 Sv. My > guess is that this was derived directly or indirectly from ICRP > Publication 60. If so, it's wrong on two counts. First, it confuses > cancer incidence with cancer mortality. Second, it implicitly takes > credit for a DDREF (Dose and Dose Rate Effectiveness Factor) of 2 which is > not applicable for the exposure described. > > Natural background is given as about 2 mSv/y, with radon accounting for > 0.7 mSv/y. These data are at variance with world averages, but may be > applicable to Australia. In particular, the radon datum seems low by > nominally a factor of 2. You may want to check your source. > > The area of highest natural background is given as Kerala at 13 mSv/y, but > then four other places exceeding 50 mSv/y are mentioned. If population > exposed is being factored in, then I miss the point in the context of the > dose rates given. What if you had another population of, say, 200 000 > each exposed to 10 mSv/y? What about 500 000 at 5 mSv/y? What about 6 > billion at 2.4 mSv/y? > > In the U-238 decay chain, the nuclide Pa-234 should be Pa-234m. These are > two distinct nuclides with different half-times and decay schemes. > Thorium-234 can decay to either, but almost always decays to the > meta-stable state, Pa-234m. The half-time you have shown is correct, but > is the half-time of Pa-234m, not Pa-234. Notwithstanding the necessity of > specifying the meta-stable state, if anyone ever tries to convince you > that these are two energy states of the same nuclide, please remind them > that a nuclide is an atom characterized by the number of protons, number > of neutrons, and energy content of its nucleus (ground state being the > default where no meta-stable state is indicated). >


> Here's my origin-of-factoids theory. > > I think typically what happens is that someone messes up some calculation > or, what's arguably worse, exaggerates some fact, and thereby cooks up > some half-baked factoid and publishes or otherwise communicates it in the > gray literature. From there, the factoid propagates, probably > geometrically. A classic example is the putative incremental dose > received from potassium-40 as a result of sleeping with another person for > a year. Of course, this is then favourably compared to that received from > living near a nuclear power station. Cute idea. Unfortunately, the > spousal-irradiation annual dose widely quoted in this hemisphere (1 mrem, > but I've even seen 4 mrem) is grossly in error. > I gave a branch seminar a few years ago entitled, "Spousal Irradiation - > Debunking the Folklore", where I presented a more supportable calculation > backed up by some confirmatory Monte Carlo work. I plan to upgrade my > overheads (and include the obligatory cartoon playing on the word > "debunking") and present this at some conference some time. > > I think another source of factoids occurs where, after someone correctly > calculates something (and perhaps even gets it peer-reviewed), the > "facts"-sheet publisher misinterprets it and completely changes the > meaning into something rather silly, and then doesn't get that properly > reviewed. Did you know that, "More than two-thirds of the radiation we > are exposed to exists naturally throughout the universe in the form of > cosmic radiation"? Maybe, if we lived on Mars; I don't know. I'm sad to > say that the above quote still appears (with other factoids) in a Canadian > nuclear-industry publication, more than ten years after I suggested (the > first of, I think, two times) that it be reviewed. They might be pulling > some stunt here like taking the (irrelevant) energy-fluence rather than > energy absorption, but if that's the case, then they should include > neutrinos! More likely, they just messed it up by misquoting some other > fact. > >


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